100个不能错过的实用JS自定义函数(5)

function isTouchScreen(){
  return (('ontouchstart' in window) || window.DocumentTouch && document instanceof DocumentTouch);
}

36、原生JavaScript判断是否在安卓上的谷歌浏览器

复制代码 代码如下:

function isNewChromeOnAndroid(){
  if(this.isAndroidMobileDevice()){
    var userAgent = navigator.userAgent.toLowerCase();
    if((/chrome/i.test(userAgent))){
      var parts = userAgent.split('chrome/');

var fullVersionString = parts[1].split(" ")[0];
      var versionString = fullVersionString.split('.')[0];
      var version = parseInt(versionString);

if(version >= 27){
        return true;
      }
    }
  }
  return false;
}

37、原生JavaScript判断是否打开视窗

复制代码 代码如下:

function isViewportOpen() {
  return !!document.getElementById('wixMobileViewport');
}

38、原生JavaScript获取移动设备初始化大小

复制代码 代码如下:

function getInitZoom(){
  if(!this._initZoom){
    var screenWidth = Math.min(screen.height, screen.width);
    if(this.isAndroidMobileDevice() && !this.isNewChromeOnAndroid()){
      screenWidth = screenWidth/window.devicePixelRatio;
    }
    this._initZoom = screenWidth /document.body.offsetWidth;
  }
  return this._initZoom;
}

39、原生JavaScript获取移动设备最大化大小

复制代码 代码如下:

function getZoom(){
  var screenWidth = (Math.abs(window.orientation) === 90) ? Math.max(screen.height, screen.width) : Math.min(screen.height, screen.width);
  if(this.isAndroidMobileDevice() && !this.isNewChromeOnAndroid()){
    screenWidth = screenWidth/window.devicePixelRatio;
  }
  var FixViewPortsExperiment = rendererModel.runningExperiments.FixViewport || rendererModel.runningExperiments.fixviewport;
  var FixViewPortsExperimentRunning = FixViewPortsExperiment && (FixViewPortsExperiment === "New" || FixViewPortsExperiment === "new");
  if(FixViewPortsExperimentRunning){
    return screenWidth / window.innerWidth;
  }else{
    return screenWidth / document.body.offsetWidth;
  }
}

40、原生JavaScript获取移动设备屏幕宽度

复制代码 代码如下:

function getScreenWidth(){
  var smallerSide = Math.min(screen.width, screen.height);
  var fixViewPortsExperiment = rendererModel.runningExperiments.FixViewport || rendererModel.runningExperiments.fixviewport;
  var fixViewPortsExperimentRunning = fixViewPortsExperiment && (fixViewPortsExperiment.toLowerCase() === "new");
  if(fixViewPortsExperiment){
    if(this.isAndroidMobileDevice() && !this.isNewChromeOnAndroid()){
      smallerSide = smallerSide/window.devicePixelRatio;
    }
  }
  return smallerSide;
}

41、原生JavaScript完美判断是否为网址

复制代码 代码如下:

function IsURL(strUrl) {
    var regular = /^\b(((https?|ftp):\/\/)?[-a-z0-9]+(\.[-a-z0-9]+)*\.(?:com|edu|gov|int|mil|net|org|biz|info|name|museum|asia|coop|aero|[a-z][a-z]|((25[0-5])|(2[0-4]\d)|(1\d\d)|([1-9]\d)|\d))\b(\/[-a-z0-9_:\@&?=+,.!\/~%\$]*)?)$/i
    if (regular.test(strUrl)) {
        return true;
    }
    else {
        return false;
    }
}

42、原生JavaScript根据样式名称检索元素对象

复制代码 代码如下:

function getElementsByClassName(name) {
    var tags = document.getElementsByTagName('*') || document.all;
    var els = [];
    for (var i = 0; i < tags.length; i++) {
        if (tags[i].className) {
            var cs = tags[i].className.split(' ');
            for (var j = 0; j < cs.length; j++) {
                if (name == cs[j]) {
                    els.push(tags[i]);
                    break
                }
            }
        }
    }
    return els
}

43、原生JavaScript判断是否以某个字符串开头

复制代码 代码如下:

String.prototype.startWith = function (s) {
    return this.indexOf(s) == 0
}

44、原生JavaScript判断是否以某个字符串结束

复制代码 代码如下: